1. Field of the Invention
This invention relates to a semiconductor light emitting device and apparatus, and more particularly to a semiconductor light emitting device and apparatus having a translucent conductive film on its light extraction surface.
2. Background Art
A semiconductor light emitting device, such as a light emitting diode (LED), that uses low-resistance metal oxides such as indium tin oxide (ITO) as a translucent current diffusion layer provided on its light extraction surface, is disclosed in JP 2004-103710A, for example.
A thick current diffusion layer is required for sufficient diffusion of current throughout the light emitting layer. However, a thick current diffusion layer increases the light absorption therein, which decreases the efficiency of light extraction to the outside of the device. On the other hand, a thin current diffusion layer is required in order to increase optical transmittance for higher efficiency of light extraction to the outside of the device. However, a thin current diffusion layer increases the lateral electrical resistance of the device, which will cause insufficient current diffusion throughout the light emitting layer. It is thus difficult to achieve compatibility between current diffusion and light extraction in the current diffusion layer.